Archive for the ‘Heliconius sapho’ Tag

No change in the weather this week. We have had another seven days of hot, sunny weather. There were two days when the clouds had formed and the sky remained overcast but no rain resulted although the temperatures plummeted from 104⁰F to 96⁰F.

The butterfly numbers are increasing but still way below what would be expected for this time of year which is normally the peak of butterfly activity. Around the pond at night, the Savage’s Thin-fingered Frogs are starting to gather in greater numbers. The pond is the last remaining damp area on site. The flowering period for many of the trees has finished and now some of them have started fruiting.

The major excitement this week has been the presence of a female Puma, (Puma concolor). She had been seen in several different locations around the grounds. The high-pitched barking alarm call of the Spider Monkeys is always an indication of where the cat is passing by. One day, as the sun was setting, the alarm calls of agitated monkeys and agoutis started the fill the air. The cat was on the prowl.

She left the cover of the forest and walked through an open garden. That is where I spotted her. She was in no hurry and it was patently obvious that she could see me. She crossed the driveway and made her way into some dense vegetation. The monkeys settling down in that area for the evening were suddenly stirred into action and more alarm calls began to build eventually reaching a fever pitch.

She emerged from the tangle of dense vegetation and slowly walked toward the edge of the cliff overlooking the ocean. An Agouti that was in the same vicinity saw the cat, let out a loud shriek and ran off with its hair stood on end. The cat immediately looked alert but then just as quickly lost interest. She sat down and started to clean herself before lying down for a few minutes. She then rose to her feet, turned her back on me and walked off into the rapidly darkening forest.

There was another predator that I managed to get very close to this week. Very close. While I was out conducting my butterfly counts I found a juvenile Broad-winged Hawk, (Buteo platypterus), sitting on a low cut tree stump on a trail through an open area of forest. It was an ideal opportunity to take a photo. I fully expected the bird to take off and fly away but it remained where it was and just looked at me. I approached closer and closer but very slowly, each time taking a photo. Eventually I ended up lying on the ground within touching distance but the bird never even flinched. I kept a wary eye to my surroundings as it was not beyond the possibility that the parent birds would be keeping watch and attack should I get too close but nothing happened.

Juvenile Broad-winged Hawk, (Buteo platypterus)

Broad-winged Hawks are migratory throughout North, Central and South America. They tend to hunt in the understory of the forest from where they swoop down and take small rodents and lizards from the ground. The broad wings and short tail are a good visual identification feature.

Close up of Juvenile Broad-winged Hawk, (Buteo platypterus)

A New Passion For Flags

Along the forest trails there are several species of Passion Vine currently in flower but this week I found one species that I had never seen before. I returned with the camera and took photos for the record and to identify this new species. –

There are sixteen species of Passion Vine to be found in the forests of the Osa Peninsula. One is seen throughout the year at Bosque del Cabo Rain Forest Lodge, the Scarlet Passion Vine, (Passiflora vitifolia). It is hard to miss the bright red flowers suspended on thin, fleshy, green stems that grow up from the ground and entwine the vegetation. Two others flower only occasionally.

The new species, Passiflora pittieri, is normally found in primary forest but at the top of the canopy or in light gaps. The flower is very distinctive with its pale cream petals and a corona of yellow-tipped orange filaments and pink-flushed anthers. This one appears to be insect pollinated as I could see bees visiting the blooms.

Passiflora pittieri

The leaves of this species are highly cyanogenic. When physically damaged they release cyanide which would normally deter most creatures from eating them. But where there is a system then there is a way round the system. There are many species of longwing butterfly the larvae of which feed on the leaves of various species of passion vine. The larvae have an enzyme that allow them to sequester the cyanide molecule and use it in turn as a toxic defense. The caterpillars can only eat the young leaves as the older leaves will have become too unpalatable.

Cydno Longwing, (Heliconius cydno)

Sapho Longwing, (Heliconius sapho)

Another insect associated with passion flowers are the flag-legged bugs. These phytophagous, or leaf-eating, members of the Order: Hemiptera, Su

border: Heteroptera and Family: Coreidae can usually be found clustered around the flowers of passion vine. Their rearmost legs have a large expanded flat and colored section.

Flag-legged Bug, (Anisoscelis flavolineata)

Flag-legged Bug, (Coreidae sp)

If a predator approaches a Flag-legged Bug, then the insect will wave one of its two brightly colored expanded rear legs. This provides a target for the attacker which will end up with little more than a leg for its efforts while the bug will have flown away. Many Flag-legged Bugs will be observed with either one or both rear legs missing.

The Pit of no Escape

This time of year with the ground having become very dry and friable, there are many small crater-like pits that have appeared all over the trails. It would appear as if a miniature meteor storm had hit the area. Further investigation, more particularly by disturbing the sides of the crater wall, will result in small grains of sand erupting upwards towards the source of the disturbance. Buried and hidden at the bottom of the pit is a larva of an insect closely related to Lacewings and Owlflies, the Antlion, and it is this larva which is responsible for throwing the sand grains.

Antlion, (Myrmelon sp), Pit

The Antlions belong to the Family: Myrmeleotidae within the Order: Neuroptera. Only antlions of the Genus: Myrmelon create the pits. The larva excavates the steep-sided pit and places itself at the bottom, just beneath the surface and covers itself with the fine sand. They don’t just feed on ants, any small insect venturing within the crater rim will find itself struggling to leave. The more it struggles to climb out, the more loose material it will dislodge causing it to slip towards the bottom. The predatory larva lying in wait will now begin its performance of death to bring down the final curtain on the life of its victim.

Mandibles of Antlion, (Myrmelon sp), Larva Grabbing Hapless Ant

Using the front legs the larval antlion flicks sand up at the ant desperately trying to escape the steep sided crater. This serves to drag it further down towards the bottom of the pit. When it finally slips all the way down, then the mandibles of the larva snap shut around the prey’s body. This is what I was observing. The unfortunate ant was struggling to escape the deadly grip of the mandibles but to no avail. Sharp projections on the inside of the mandibles pierce the ants body and the larva sucks the juice out of the ant. Once it has finished the remaining dry and drained carcass is flicked out of the pit while the larva awaits a fresh potential food item to enter.

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

Black and yellow is the most visible color combination that exists. It follows that any creature sporting patterns in this visually obvious blend might not be trying to conceal itself. Bees, wasps and hornets are generally striped in yellow and black. Many poisonous spiders, butterflies and caterpillars are decked out in the same fashion. If they are not trying to hide then they are making themselves obvious, for whatever reason they are telling you to stay away. This strikingly acute combination of color is known as aposematic coloration or warning coloration. Humans use it too in the form of black and yellow striped tape to keep people from getting too close to a dangerous situation.

In the area of Matapalo these colors can be frequently seen and encountered throughout the forest. Flying along the forest rides and around the nectar giving bush Lantana camara in gardens are the brightly colored Heliconiids or longwinged butterflies. One of the most common of these is Heliconius sapho, its yellow banded velvet black wings beating slowly interspersed between periods of short glides as it makes its way down the trails. This aesthetic beauty is telling potential predators one thing – “STAY AWAY”.

The butterfly is unpalatable and what makes it unpalatable is the fact that it is packed with cyanide. Having a toxic defense against predation serves no purpose if the predator does not know about it. Eating one of these butterflies would result in the death of the butterfly and the creature eating it. The predators learn through experience. Once a predator, whether it be a bird or a lizard, catching and trying to feed on one of these butterflies will experience a foul taste caused by the cyanide. It spits it out and it does not take too long before the black and yellow coloration is associated with something so wholly unpleasant that anything dressed in the same colors will be avoided with a passion.

Leaf it Alone

It is not just adult Lepidoptera that use toxic defenses; many caterpillars are prone to do the same. Frangipani, (Plumeria rubra), despite being thought of as a Hawaiian plant whose flowers are used to make the leis to put around the necks of tourists, is actually native to Central America. It is the national plant of Nicaragua.

Frangipani continually flowers throughout twelve months of the year. As the sun sets the pale white blossoms give off a heavenly scented sweet perfume which drifts into the night, the aroma of which attracts night-flying hawk moths. The moths are attracted with the promise of a nectar rich feed. But nectar is energy expensive for the plant to produce so the plant cheats the moth; it reneges on the promise and produces no nectar at all. The duped hawk moth searches in vain but to no avail, the long proboscis probes into one flower after another and becomes covered in pollen. Flying from flower to flower it transfers the pollen and pollinates the plant. The moth having thus been enticed subsequently receives no reward for its labors.

There are moths that unwittingly have their revenge, the Frangipani Hawk Moth (Pseudosphinx tetrio). The eggs of this moth are laid on the undersides of the Frangipani leaves. Upon hatching the caterpillars are very small, only 10 – 15 mm. They won’t stay that way for long. After consuming their own egg shell they set about consuming the leaves with gusto. The caterpillar is a committed eating machine; it turns plant tissue into animal tissue at an incredible speed. They can almost be seen to grow day by day.

The last part of the leaf to be eaten is the stalk. If damaged the stalk leaks a stiff white liquid rich in alkaloids. The alkaloids are very toxic and would normally deter anything from consuming the leaf. The Frangipani Hawk Moth caterpillars store the alkaloids in their bodies making them in turn highly toxic. Once more that information needs to be relayed to any potential predator to save both parties from harm. The vividly black and yellow hoops with a flash of bright red head, tail and legs should serve the purpose very well. It appears to do so as these caterpillars feed in full view both day and night on the very naked limbs of the Frangipani.

Within little more than a week the plant will be denuded of leaves and the caterpillars will have increased to a very stout 60 – 70 mm. Should more plant tissue be needed to complete the larval stage before pupation then the caterpillars set about consuming the rubbery branches of the tree. One night, as if by magic, all the caterpillars will have disappeared, retiring to some secluded nook or cranny to pupate before emerging in the future as a relatively drab moth which will mate and start the process over again. Although the Frangipani may look a little forlorn in its leaf denuded state, it really doesn’t take long for it to produce fresh growth, in fact quite often on parts of the plant as the caterpillars are still feeding.

Beware a Colorful Meal

Spiders might not be that easy to find but once you start to look they are everywhere. In common with many other forms of life, the species richness and diversity of spiders is huge. More obvious than most are the orb weaving spiders, the webs of some species traversing large expanses between trees. However there are many smaller spiders with consequently smaller webs. One of the more distinctive of these is the Arrow-bodied or Spiny-bodied Spider, (Micrathena sexspinosa). Either name is appropriate and speaks for itself.

The body of the spider has an array of spines and thorns which in itself should be enough to discourage any potential predator. But sometimes physical defenses can be overcome. The spider has invested in a second insurance policy – a foul-tasting chemical defense. As with the above butterflies and caterpillars there is no point having that means by which to avoid predation if the predator is oblivious to its existence. So once again aposematic coloration comes into play, the spider is dressed in a black and yellow checkered pattern.

Any naive bird or lizard that ignores the warning signs and tries to eat the spider will end up with the spider jammed in its bill or mouth by way of the spines and thorns. All the while the spider issues from its skin a nasty tasting secretion that the unfortunate predator has to endure while trying to remove the spider from its bill or mouth. Once the cause of the vile experience has been eliminated then the bird or lizard will probably never attempt to eat anything black and yellow again.

Tiny Timid Tigers

For the last example of black and yellow aposematic coloration we turn to the hymenoptera, more specifically the ants. Ants like spiders may not at first be as obvious as mammals, birds and butterflies but take the time to look at little more closely and they most certainly are there. Leaf-cutter Ants are hard to miss, their long winding ribbons of green cut leaf fragments running like verdant rivers across the forest floor. Army Ants likewise when in a foraging frenzy move in fronts upto sixty feet across appearing as an almost large black plastic sheet being pulled across the forest floor, its intent being the slaughter and butchering of all small forms of life unfortunate enough to not be able to escape from its path. Noisy excited attendant birds and the hum of parasitic flies usually herald its approach.

But rather than these mass movements there are many other ants that occur in smaller numbers. Seen walking down tree trunks, along branches and roots in small lines like kids playing follow the leader are distinctive black ants with golden bands, the Tiger Ants, (Camponotus seriseivestris).

Tiger Ants are closely related to the Carpenter Ants and share the same life history as general foragers taking nectar, seeds and fruit from plants. They attend aphids and certain Lycaenid caterpillars for honeydew as well as taking small creatures either dead or alive. They live in colonies in hollows within dead or living trees but in much smaller numbers than Leaf-cutter or Army Ant colonies.

The name Tiger Ant conjures up visions a seriously ferocious adversary capable of doing limitless damage to any unsuspecting tourist that accidently puts his hand upon them. In actual fact they are harmless, most certainly to humans, the name referring to the coloration rather than their nature. They do however have a means of defense if disturbed. The aggravated ant will turn its abdomen between its legs so the rear end is facing forwards and then it will shoot a jet of formic acid towards its aggressor. Many ants indulging in the same defensive strategy will generally deter the cause of its ire to retreat to a safe distance.

Philip Davison is a biologist, writer and photographer based in Costa Rica.

The weather continues in the same pattern with a day of rain followed by several more days of dry and sunny conditions. With every prolonged spell of dry weather the land crabs and frogs, which are at first abundant, reduce steadily in numbers. Then with the rain, out they come again. At the pond at this time of year it is always the Milky Frogs, (Trachycephala venulosa), that come out, pair up and lay eggs within hours of an evening of heavy precipitation. Their periodic spawning should ensure an adequate food supply for the Cat-eyed Snakes, (Leptodeira septentrionalis), at least for the near future until the normal pattern of rainfall is resumed.

The Black and Green Poison Arrow Frog, (Dendrobates auratus), numbers also wax and wane with the sun and rain. Most days they can be found on the Creek Trail behind the Bosque bar and in especially large numbers if it has rained the night before.

When the crabs do emerge in large numbers they run the risk of attracting an equally large increase in the number of predators coming into their vicinity to feed upon them. White-nosed Coatis, (Nasua narica), are related to raccoons and just like their cousins will take most eating opportunities afforded them. As the crabs are now moving freely on the surface of the soil in broad daylight, the coatis have no problem picking them off with ease. Subsequently there are currently a lot of remains in the form of discarded crab legs and carapaces lying around the grounds and a lot of well sated coatis.

Expected Visitors

There was excitement from the staff one night at the bar while all the guests were eating. I was called over to see a coral snake. It is not uncommon to see coral snakes but they do tend to be nocturnal in habit and so not always active when people are around. They are also very secretive and despite the brightly colored bands warning you of their potentially lethal bite, they are normally found under leaf litter or around the compost heap which is where they seek their preferred prey items which include sleeping lizards and smaller snakes.

This individual was an Allen’s Coral Snake, (Micrurus alleni), the largest of the Costa Rican coral snakes and this one was long, being a good 3 feet in length. None of the staff had seen a coral snake this size before. It made its way along the edge of the path, its tongue constantly flicking in and out, sampling the scent in the air. It finally found a small hole in a rotten tree trunk into which it quickly slipped and disappeared.

I had a pleasant surprise one day by my bathroom, an Eyetail Moth, (Sematura luna), was resting on the wall. The wall is a stark bright white but the moth was at the perfect height to get the spread of its wings full in the frame of the picture.

The wings are a rich purple brown color with two pale bands and a concentric series of scalloped creamy colored lines. It has two distinctive tails, each one sporting the large eyespot at its base that gives the moth its name.

The Eyetail Moth is a nighttime flying moth related to the day flying Green Uranias, (Urania fulgens). Despite the fact that they are not necessarily rare, very little is known about the early life history of this moth.

There have been a few other visitors in the vicinity of my garden over the past week, all nocturnal. Later in the evening up in the tree tops by my cabin and over the course of several nights, I could hear Kinajous, (Poto flavus) moving around, their presence being announced not only by moving vegetation but also the distinct nasal “honk” followed by soft whistling.

The Fire Beetles are still around, two bright green bioluminescent spots punctuating the darkness as they crawl around on the bark of trees. If they fly, then the abdomen lights up a glowing fiery orange, unmistakable as they swirl through the darkening dusk air.

One more visitor that not everyone likes, but I have a certain fondness for, is the Terciopelo, (Bothrops asper). For the past two weeks one has been coming out and curling up in the same place, then disappearing for a few days. Given some respect and some distance, you should not have any problem with them. Just as with most snakes they would rather shun the company of humans. This one allowed me to photographic it before registering its displeasure by moving off. Every time I set the camera to get another shot, it moved once again, so eventually I gave up and left it in peace to go about its own business.

Don’t Whip Poor Will

One bird that I have been meaning to photograph and add to bestiary of nocturnal creatures that I regularly see on the night tour is the Common Paureque, (Nyctidromus albicollis). These birds are related to night hawks, whip poor wills and goatsuckers. They are nocturnal, insectivorous birds that both roost and nest on the ground.

The coloration of the plumage is a mixture of browns, tans and grays which are then subtly suffused with pale spots. This cryptic coloration is very effective at blending the bird in with the background of dead leaves amongst which it sits on the forest floor during the day, perfectly camouflaging its presence from predators.

The Paureque has another trick under its wing; it doesn’t give off an odor. Most ground living predators find their prey through sight and scent so with the Paureque they can neither see them nor smell them, so the bird is very well adapted to living on the ground.

One of the basic principles of camouflage is that you don’t move because to do so would blow your cover. If they are caught in the beam of a flashlight, the Paureque sits quite still hoping that you cannot see it. But as anyone who has been out on the night tour with me will know, the eye shine of a Paureque is not dissimilar to two flaming coals in the darkness, so we can spot them a long way off.

The Paureque reproduces in February – March. At that time the female will have a scrape in the ground which will serve as a nest. She generally sits on two eggs. If you approach at night when she is incubating the eggs, she sits tight and hopes that you will pass by without having seen her.

Once the chicks hatch, every night they will be approximately 10 feet away from where they were the night before, they are continually moving from one night to the next. Now is you approach the female she will jump up and down in front of you, but always just out of reach. She drags her wing, feigning injury. She will lead you further and further away from the chicks and once she thinks you are at a safe distance; up she goes into the sky and disappears.

At the moment there are still several males who sit at various points around the grounds. Earlier in the year they were quite vocal but now just sit in silence. They have a characteristic flight where they flutter up, catch an insect and flutter back down again. When they do fly, they are silent. The males have a distinctive white wing bar which can clearly be seen as the phantom-like avian insectivore silently takes to the air and almost hovers over your head before heading to a safer refuge further away.

I had to approach the bird quietly and try to set up the camera equipment with one hand while holding the bird in the flashlight beam. Normally as soon as the light beam is removed, the bird goes without a sound. I managed to get two shots before it took flight but fortunately it didn’t land too far away. Again, going through the same procedure I managed to get the camera in place and get one shot before the bird again left but this time to an unseen location.

Philip is a biologist, writer and photographer as well as the onsite naturalist guide at Bosque del Cabo Rainforest lodge on the Osa Peninsula, Costa Rica.

One day at around noon, I was down by a patch of Lantana photographing butterflies for a new book of butterflies at Bosque. Being midday, the sun was overhead and intensely bright which doesn’t generally make for good photos, there being a very high contrast between light and dark. Also at that time of day the butterflies don’t stay still for very long, they momentarily land, feed and flit off again. Nonetheless I was trying to get some images of the many longwing butterflies that commonly visit the Lantana and was using the shade of the plant along with flash to get the pictures.

Two butterflies caught my attention. One butterfly was sitting on a leaf, wings extended and its abdomen raised. The other was hovering directly above it moving up and down as if attached to a spring suspended beneath a higher branch, its wings fluttering continuously. This was the courtship behavior of Tiger-striped Longwing, (Heliconius ismenius), and as luck would have it right in front of the lens of my camera. I have reported on this behavior before and it is not uncommon to see male butterflies courting a female but it is not always easy to get the shot.

The male butterfly initially has to recognize a female of his own species which is generally a visual cue, before he can court her. To solicit a positive mating response from the female, the male now has to woo her with chemical aphrodisiacs, (pheromones), called “love dust” emitted from specialized glands, androconia, (modified scales), normally found under his wings. As he is fluttering up and down, the rain of olfactory stimulants will coat the female’s antennae.

Most female butterflies will mate within a short time after emerging from the chrysalis. There is a good chance, as in this case, the female will already have accepted a suitor and has no interest in the male now attempting to entice her. She signals her lack of desire by spreading her wings and holding her abdomen high. This male will have to try his luck elsewhere.

The weather continues to favor the visitors to the Osa Peninsula. August normally sees the transition from rain to really heavy rain which continues through September into November. But the days remain hot and sunny, and certainly not every night, but definitely last night, we were entertained by an electric storm with lots of lightning illuminating the forest and lodge accompanied by the crashes of thunder which rattled the structure of all the buildings. All of this, along with the driving rain lashing down, probably made for a sleepless night for one and all. This morning though, as the sun rose over the Golfo Dulce, it did so without a cloud in the sky, promising yet another beautiful day.

Rainforest Rhythm

The storm seemed to have dampened the enthusiasm of the animal life as there were not many birds active at first light and the butterflies made a slow start of it but as I sit and write at mid day everything appears to have returned to normal activity. The Scarlet Macaws are making their usual raucous din and a large flock of Golden Hooded Tanagers have been making their way from one fruiting tree to another, eagerly feeding on the ripening feast now available to them.

The grounds have several fig trees which have been producing a copious amount of small figs for several weeks now. Toucans arrive by the flock on a daily basis. There are large mixed flocks of multiple tanager species, dacnis, honeycreepers and manikins. The ever-present large white blooms of the Crepe Gingers are continually attracting the attention of resident Rufus-tailed Hummingbirds and Purple-crowned Fairies which feed on the nectar they provide. Despite their small size, the Rufus-tailed Hummingbirds zealously guard their food supply, pugnaciously putting much larger invaders of their territory to flight. The Hermits, both Long-billed and Strip-throated, are more tranquil by nature, and “trapline” the Heliconia blooms, making their daily rounds, flitting at high speed from flower to flower, hovering briefly at each one to take a sip of nectar.

The Hobos or “Hog Plums” have been another month’s long source of fruit now and the Cannonball Tree which has recently been flowering is now starting to produce the distinctive large cannonball shaped fruits from which the tree derives its name.

Rain in A Rainforest: Life Goes On

This is not the best time of year to see butterflies but nonetheless there are some persistent species, particularly some of the brightly colored long-wings. I don’t tend to put many guarantees on wildlife sightings, but I can be pretty sure that a visit to one of the constantly flowering Lantanas in the garden areas will reward you with at least four or five species, taking it in turns to move between the orange and yellow flower heads.

Monkeys, coatis and agoutis are not going to be to far away on any day in this area. Many people ask what the animals do during the rainy season. It is a rainforest, it rains seven months out of twelve so the animals go about their daily lives as normal. The Humpback Whales have been giving a fine display today. Several visitors sitting on the deck of their cabins have seen females with calves close to the shore.

So despite a slow wet start, today turned out just fine, another beautiful day, in more ways than one, here on the Osa Peninsula.

Wildlife spotting is a bit of a hit or miss affair. No nature guide in his right mind would give cast-iron guarantees about seeing any one particular animal, even it is has inhabited the same spot for a long period of time. Animal life is not always compliant with ones wishes to see it. Despite the high levels of biodiversity in tropical rainforests, notoriously they do not reveal their secrets very readily. It is not like being on the African savannahs inhabited by large mega fauna. If mammals don’t want to be seen, you will not see them. I have lived here for ten years and I walk these trails on a daily basis. In the wet season I can see what has been walking before me from the tracks they have left in the soft earth. I have seen the tracks of Baird’s Tapir on more than a few occasions. It is an animal about the size of a Shetland Pony and despite having seen their tracks, even close to my cabin, I have never seen a tapir in this area.

Obviously Aposematic

However there are animals that do want to be seen. One can think of the bright red color of the Scarlet Macaw. Along with many other species of parrot, macaws are gregarious birds. Red is the complementary color to green, the background color of the forest, so it probably aids the macaws as a visual signal within the group. Think of all those brightly colored, slow flying butterflies, the Heliconiids or Long-wings. Why would a butterfly want to appear so visibly obvious, they are patently not trying to hide? The reason is that they contain cyanide. It would not be in the interests of any predator to feed on the butterfly and nor would it do the butterfly any good to have such a toxic chemical deterrent if nothing new about it. So those bright flashy colors are warning colors and animals sporting them are said to display aposomatic coloration.

Heliconius sapho

This situation very nicely lends itself to two forms of mimicry. Batesian mimicry is the term applied to non poisonous butterflies mimicking poisonous butterflies. This form of mimicry only works where there are far more poisonous butterflies or the predators would never learn. Mullerian mimicry is where all the poisonous butterfies across the board are co-mimics of one another. And mimicry really does work, quite often you need the butterflies in your hand to assess subtle differences in markings or coloration to allow you to identify one species from another.

Heliconius cydo – Can you tell the difference with the species above?

Most amphibians are nocturnal, so any diurnal amphibian hopping around on the forest floor during the day is going to be a fairly easy target. To this effect many diurnal amphibians have evolved very toxin skin secretions. But once again, there is no point having a toxic skin secretion if none of the predators know about it. If they eat the frog it is too late for them and too late for the frog. Diurnal frogs such as the poison dart frogs have evolved very bright warning colors, another example of aposematic coloration. The colors tend to be neon-like and almost glow from the forest floor. If something is sitting there glowing, it is not inviting itself as a meal, it is telling you to keep your distance.